Help With Jam-O-Matic

[saibot]

I have two identical STI TruBor 9mm Open guns and one of them has always had the occasional jam (see picture below). It started getting worse and would jam once per stage last time out. It has happened with both STI and MBX magazines, all fairly new. I've tried 8 - 11 lb recoil springs. The ammo is all tested before shooting in my Hundo. Using a Lee U-die/seating/FCD. Everglades 115 JHP, but has had the same issue with Montana Gold 124 JHPs as well. OAL is around 1.158ish. This pistol has about 3k on it. The other TruBor has around 9k on it, and jams occasionally, too. And for what it's worth, I've recovered the rounds that jammed and they look find, and case gauge fine as well.

 

Any advice/tips/things to investigate would be great! Loosing my mind.

 

Thanks!

 

 

[bigbob21]

Had the exact exact same problem all last year...

 

It’s gotta be the extractor... too much tension is slowing down the round on its way up and into the chamber.

 

For me, mine was cracked, so sometimes it had too much tension. Other times it had too little tension. Was very hard to diagnose due having signs/symptoms of both.

 

Replaced and fit 2 new Ed brown extractors (one for backup) and the gun has been running fine ever since.

 

FYI: I run the same bullet, oal, mags, as you’ve mentioned.

Goodluck

 

 

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[saibot]

2 minutes ago, bigbob21 said:

Had the exact exact same problem all last year...

It’s gotta be the extractor... too much tension is slowing down the round on its way up and into the chamber.

For me, mine was cracked, so sometimes it had too much tension. Other times it had too little tension. Was very hard to diagnose due to having both symptoms.

Replaced and fit 2 new Ed brown extractors (one for backup) and the gun had been running fine ever since.

FYI: I run the same bullet, oal, mags, as you’ve mentioned.
Goodluck


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I think you just made my day.

That would explain the issues exactly. Would you suggest trying to get the EB or just spring for the Aftec?

 

Thank you for the post!

[Explosiveo]

You could also try increasing your oal. I run 1.165- 1.170

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[saibot]

6 minutes ago, Explosiveo said:

You could also try increasing your oal. I run 1.165- 1.170

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I wonder if I can go much longer. The 115's don't have that much left in the case when I get them out there. 

 

Missed you last weekend. Get tired of beating everyone?

[bigbob21]

I think you just made my day. [emoji4] That would explain the issues exactly. Would you suggest trying to get the EB or just spring for the Aftec?  

Thank you for the post!

 

 

 

  I’m not experienced enough with aftec to say yes or no.

I heard it was top of the line in the past, but right now I see people switching away from it.

 

To reply to the other comment about oal.

The reduced oal under 1.16 was likely a bandaid to the underlying problem. Bullets weren’t going in for me due to the extractor tension. A reduced length got stuck a bit less often.

 

I’m sure you could pull the length back out once everything gets sorted out, but I never did.

I still load to 1.160+/- in my gun and it feeds just fine.

 

 

 

[Explosiveo]

Haha. I went to the Magnus match in St. George.

I run 115 Everglades and they seem to have plenty at in the case at 1.17.

I would think it would help. Everyone I talk to runs their rounds as long as possible.

Also aftec extractors are the s#!t. But I would think that only effects stripping the fired round. Not loading the round. However I am not 100% sure on that

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[saibot]

Well, it couldn't hurt. Just ordered an Aftec from Dawson Precision. 

 

I'll also see if I can get the OAL a little longer and see if it helps until the Aftec arrives.

 

Appreciate the help!

[Explosiveo]

Anytime brother. Always glad to help.

From everything I know loading issues are oal and mag tuning.

Aftec MAY need to be fitted.

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[ParaGunner]

The extractor has a lot to do with chambering a round. The case rim slides under the extractor hook during feeding. Too tight causes feeding jams, to loose causes ejection issues. 

[Glk21C]

It's the extractor tension that is off.  Since you have an Aftec on the way it is NOT UNUSUAL to have to fit them to each gun, they are almost never a drop-in part.   A lot of folks love them, some don't.  I've always felt they were a solution to a problem that does not exist but that's just me.

If the gun with the current extractor does not appear to be broken (the extractor) why not just re-tension it first?  Also, I would suspect your jams happen more frequently with a big stick than it does with your 140's.  Extractor tension problems start rearing their ugly head first using big sticks but when it gets bad enough it will give you fits in all size magazines.

 

good luck, hope it all works out

[lcs]

AFTEC only requires clocking the FP stop one time.  Instructions can be found anywhere.  I have used AFTEC on every open gun I have owned.  I've never had an AFTEC go bad, never needs adjusting-maybe a spring change once in a while.

 

[Fo0]

9 hours ago, bigbob21 said:

  I’m not experienced enough with aftec to say yes or no.

I heard it was top of the line in the past, but right now I see people switching away from it.

 

To reply to the other comment about oal.

The reduced oal under 1.16 was likely a bandaid to the underlying problem. Bullets weren’t going in for me due to the extractor tension. A reduced length got stuck a bit less often.

 

I’m sure you could pull the length back out once everything gets sorted out, but I never did.

I still load to 1.160+/- in my gun and it feeds just fine.

 

 

 

 

I think they only reason more people using tool steel extractors is there are multiple companies making them and I think there is only one company currently making the spring steel extractors. Atlas is supposedly making a spring steel version similar to the Aftec. Atlas said the original 1911 extractor was spring steel but only one manufacturer currently. 

[lcs]

10 hours ago, saibot said:

I have two identical STI TruBor 9mm Open guns and one of them has always had the occasional jam (see picture below). It started getting worse and would jam once per stage last time out. It has happened with both STI and MBX magazines, all fairly new. I've tried 8 - 11 lb recoil springs. The ammo is all tested before shooting in my Hundo. Using a Lee U-die/seating/FCD. Everglades 115 JHP, but has had the same issue with Montana Gold 124 JHPs as well. OAL is around 1.158ish. This pistol has about 3k on it. The other TruBor has around 9k on it, and jams occasionally, too. And for what it's worth, I've recovered the rounds that jammed and they look find, and case gauge fine as well.

 

Any advice/tips/things to investigate would be great! Loosing my mind.

 

Thanks!

 

 

 

 

Those look like Zero JHP, have you tried other bullets?  115 PDs are designed differently.  Sometimes a gun just doesn't like a particular bullet shape.

[Explosiveo]

 
 
Those look like Zero JHP, have you tried other bullets?  115 PDs are designed differently.  Sometimes a gun just doesn't like a particular bullet shape.

I had that issue as well. My old gun wouldn't run PD but ran Everglades JHP V2 perfecly.

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[Hi-Power Jack]

9 hours ago, saibot said:

I wonder if I can go much longer.  

 

My TruBors both run fine with 1.145" - 1.170".

 

(That's with MG 124/115 JHP's).     

[Chillywig]

I'd look at mag lips? Are they in spec/too wide in the front? Bullet profile? Would a FMJ feed from that same position? Extractor tension?

[lcs]

1 hour ago, Hi-Power Jack said:

 

My TruBors both run fine with 1.145" - 1.170".

 

(That's with MG 124/115 JHP's).     

 

11 hours ago, saibot said:

I have two identical STI TruBor 9mm Open guns and one of them has always had the occasional jam (see picture below). It started getting worse and would jam once per stage last time out. It has happened with both STI and MBX magazines, all fairly new. I've tried 8 - 11 lb recoil springs. The ammo is all tested before shooting in my Hundo. Using a Lee U-die/seating/FCD. Everglades 115 JHP, but has had the same issue with Montana Gold 124 JHPs as well. OAL is around 1.158ish. This pistol has about 3k on it. The other TruBor has around 9k on it, and jams occasionally, too. And for what it's worth, I've recovered the rounds that jammed and they look find, and case gauge fine as well.

 

Any advice/tips/things to investigate would be great! Loosing my mind.

 

Thanks!

 

 

  

 

In my experience the nose up jam is the OAL is just too long.  Before you try to install another extractor...  Reduce you load by a grain or so and shorten your OAL to 1.150 . If the nose up jams dissappear,  you know the problem.  Then work your load back up to major.  Depending on the powder---you don't have to load long.  Watch the primers as you work you way back to back to major and you can adjust the OAL longer until the nose up happens again.  

[B_RAD]

I just recently had similar issues with a new gun. 

 

In my case the ammo wasn't clearing the mag all the way. The end of the case was still in the mag. 

 

I switched to mags with thighter feed lip dims and new mag springs and followers. No more issues. 

 

If it happens again, check to see if the base of the case is still in the mag. 

 

If it clears the mag, then I'd guess it's the extractor like others have already mentioned.

 

 

[Absocold]

If all the previous tips don't help, remove the slide and check the magazine height when latched in the gun. If the mags and ammo work fine in one gun but not its twin gun and there isn't an extractor issue, maybe the mag catch has a problem.

 

Next, check the bolt face and firing pin hole for burrs - lightly polishing this area never hurts. Check the barrel throat and top of the chamber for problems. Check the area where the barrel chamber impacts the frame for anything that might prevent the barrel from fully tilting down. Check the guide rod for damage (especially the fat end) and verify the correct recoil spring is installed.

[Chris iliff]

On 5/3/2019 at 10:33 AM, lcs said:

AFTEC only requires clocking the FP stop one time.  Instructions can be found anywhere.  I have used AFTEC on every open gun I have owned.  I've never had an AFTEC go bad, never needs adjusting-maybe a spring change once in a while.

 

I use aftec exclusively in my Open gun. I have had 3 different occasions over the years that resulted in malfunctions that cost me tons of point. Two broken ears on the cup and one broken spring. Yes, believe it or not, one of those little springs broke in half. 

 

All malfunctions happened mid Match. 

 

So, I can see the switch to a good one piece extractor being beneficial.   Simply less to go wrong. 

 

YMMV. 

[zzt]

Later Aftecs are not as good as the earlier ones.   For one thing, their quality control sucks.  I recently returned one that was so short a case rim would not fit under it.  I replaced it with an EGW HD extractor.  I'm fitting HDs to my other Open guns in case the Aftecs fail.

[TONY BARONE]

Breech face to extractor hook plays a big part in feeding if not correct feeding will never be reliable.

[Absocold]

Never saw the point of an Aftec. Always seemed like a Rube Goldburg device, solving a problem with a fancy part instead of just tuning the original that has less things that can go wrong with it down the line.

 

The biggest problem I've seen from Aftec's is that no one wants to pull the fiddly thing out for cleaning and risk losing tiny parts. Extractor tunnel gets full of gunk and "Voila!", failures to extract.

[saibot]

Just an update. I received an Aftec extractor and watched a few YouTube reviews of it before putting it in. I opted to install without using both springs (I left out the one closest to the muzzle). The instructions mention that fitting may be required here and there, but I thought I'd try it out without doing anything.

There was a local match yesterday and I arrived early to see if the gun would cycle and put 2 140mm mags through it without issue. Then proceeded to shoot the entire match without a single malfunction. I think you guys nailed it!

THANK YOU ALL FOR YOUR HELP!!!! That was the first match in a long time without a failure.